19/(x²+x-12)≥0x²+x-12=0⇒x1+x2=-1 U x1*x2=-12⇒x1=-4 U x2=3 + _ +_______________________________________ -4 3x∈(-≈;-4) U (3;≈)2x²-5x=2x-52x²-7x+5=0D=49-40=9x1=(7-3)/4=1⇒y1=2*1-5=-3x2=(7+3)/4=2,5⇒y2=2*2,5-5=0(1;-3) U (2,5;0)2x²+7x-4=x²-16 x≠-4 U x≠=4x²+7x+12=0x1+x2=-7 U x1*x2=12x1=-4-не удов услx2=-3